The present invention relates to a method and equipment of manufacturing an arc-like formed product constituting a part of a cylinder from a band-like sheet strip of metal and is suitable for manufacturing bearings, bushings, liners or the like.
In the prior art, this kind of product has been manufactured by press forming and roll forming of sheets of steel, aluminum and copper alloy or band-like sheet strips which are formed in two layers by their metals. Generally, the press forming requires dimensional accuracy of inner and outer dies, and wear and tear of the die is substantial. Therefore, many man-hours are required for mending such a die. Also, pre-forming is required under certain circumstances before press forming. In the roll forming, when bending is performed without surrounding periphery of the sheet strip piece, cracks easily occur and the dimensional accuracy is reduced when the metal strip has a deviation in thickness. Use of bender in bending process is being tried for manufacturing this kind of product, but the dimensional accuracy has not been obtained because of spring back after processing.